In field irrigation systems, the upright, or ground irrigation heads are connected to lateral, or field supply conduits, the latter of which may supply water to a number of such irrigation heads. It is often necessary to disconnect an irrigation head from its supply conduit because the irrigation head must be removed for repair or replacement; this should be possible without affecting the supply of water to the other irrigation heads also connected to the same supply conduit. For this purpose, so-called "disconnects" are provided at the junctions between the local conduits feeding the irrigation heads and the field supply line. These disconnects are intended to allow the respective heads to be individually disconnected without disrupting the water supply to the remainder of the irrigation heads. The devices previously used for this purpose have proven to be unsatisfactory, mainly due to the failure because of contamination of the sealing parts, such failure occurring because of no provision for adequate flushing during the connect and disconnect cycles.
The same considerations apply with respect to other fluid distribution systems using automatic disconnects between fluid supply lines and local conduits feeding devices to be supplied with working fluid, such as hydraulic fluid distribution systems and pneumatic fluid distribution systems, as well as domestic irrigation systems.
A preliminary search of the prior art shows the following representative U. S. patents as indicating the present state of the art: Nos.
2,797,703--Edwards PA1 3,163,178--Stratman PA1 3,348,575--Simak PA1 3,478,762--McCullough PA1 3,626,980--Svensson PA1 3,642,037--Cunningham